As with configuration files you can use dots in collection name to define a path for configuration settings. The top_level setting is also supported to bypass that behaviour. Note too that the fwissr collection is by default a top_level configuration (as the /etc/fwissr/fwissr.json configuration file).

The /etc/my_app/my_app.json configuration file and the production mongodb collection are read only once, whereas the settings holded by the /etc/my_app/stuff.json configuration file and the config mongodb collection are expired periodically and re-fetched.

The default freshness is 30 seconds, but you can change it with the fwissr_refresh_period setting: